Leonard Nimoy’s death in February brought to a close his unusual career continually playing a single role for half a century. Between 1966, when the television show “Star Trek” premiered, and 2013, when the movie “Star Trek Into Darkness” hit the screens, Nimoy portrayed the franchise’s beloved first officer, Mr. Spock, in two TV series and eight films.

As he acknowledged, the key to “Star Trek’s” longevity and cultural penetration was its seriousness of purpose, originally inspired by creator Gene Roddenberry’s science-fiction vision. Modeled on “Gulliver’s Travels,” the series was meant as an opportunity for social commentary, and it succeeded ingeniously, with episodes scripted by some of the era’s finest science-fiction writers. Yet the development of “Star Trek’s” moral and political tone over 50 years also traces the strange decline of American liberalism since the Kennedy era.

Captain Kirk and the Cold War

Roddenberry and his colleagues were World War II veterans, whose country was now fighting the Cold War against a Communist aggressor they regarded with horror. They considered the Western democracies the only force holding back worldwide totalitarian dictatorship. The best expression of their spirit was John F. Kennedy’s Inaugural Address, with its proud promise to “pay any price, bear any burden, meet any hardship, support any friend, oppose any foe, in order to assure the survival and the success of liberty.”

This could have been declaimed by Captain James T. Kirk (played by William Shatner), of the starship U.S.S. Enterprise, who, as literature professor Paul Cantor observes in his essay “Shakespeare in the Original Klingon,” is “a Cold Warrior very much on the model of JFK.” In episodes like “The Omega Glory,” in which Kirk rapturously quotes the preamble to the Constitution, or “Friday’s Child,” where he struggles to outwit the Klingons (stand-ins for the Soviet menace) in negotiations over the resources of a planet modeled on Middle Eastern petroleum states, Kirk stands fixedly, even obstinately, for the principles of universal freedom and against collectivism, ignorance, and passivity.

Kirk loves peace, but he recognizes that peace without freedom is not truly peace.

In “Errand of Mercy,” the episode that first introduces the show’s most infamous villains, he cannot comprehend why the placid Organians are willing to let themselves be enslaved by the Klingon Empire. Their pacifism disgusts him. Kirk loves peace, but he recognizes that peace without freedom is not truly peace.

This was not just a political point; it rested on a deeper philosophical commitment. In “Star Trek’s” humanist vision, totalitarianism was only one manifestation of the dehumanizing forces that deprive mankind (and aliens) of the opportunities and challenges in which their existence finds meaning.

For Freedom of Choice

In “Return of the Archons,” for example, Kirk and company infiltrate a theocratic world monitored and dominated by the god Landru. The natives are placid, but theirs is the mindless placidity of cattle. In the past, one explains, “there was war. Convulsions. The world was destroying itself. Landru…took us back, back to a simple time.” The people now live in ignorant, stagnant bliss. Landru has removed conflict by depriving them of responsibility, and with it their right to govern themselves.

Landru has removed conflict by depriving them of responsibility, and with it their right to govern themselves.

When Kirk discovers that Landru is actually an ancient computer left behind by an extinct race, he challenges it to justify its enslavement of the people. “The good,” it answers, is “harmonious continuation…peace, tranquility.” Kirk retorts: “What have you done to do justice to the full potential of every individual? Without freedom of choice, there is no creativity. Without creativity, there is no life.” He persuades Landru that coddling the people has stifled the souls it purported to defend, and the god-machine self-destructs.

This theme is made more explicit in “The Apple,” perhaps the quintessential episode of the original Star Trek. Here Kirk unashamedly violates the “Prime Directive”—the rule forbidding starship captains from interfering with the cultures they contact—by ordering the Enterprise to destroy Vaal, another computer tyrant ruling over an idyllic planet.

Like Landru, Vaal is an omniscient totalitarian, and he demands sacrifices. The natives, known only as “people of Vaal,” have no culture, no freedom, no science—they do not even know how to farm—and no children, as Vaal has forbidden sex along with all other individualistic impulses. This sets Kirk’s teeth on edge. There are objective goods and evils, and slavery is evil because it deprives life forms of their right to self-government and self-development.

Kirk believes there must be deeper, universal principles underlying and limiting diversity, to prevent its degeneration into relativism and nihilism.

What differentiates “The Apple” from “Archons” is Spock’s reaction. In the earlier episode, he joined Kirk in condemning Landru; now the half human/half Vulcan is reluctant to interfere with what he calls “a splendid example of reciprocity.” When chief medical officer Leonard “Bones” McCoy (DeForest Kelley) protests, Spock accuses him of “applying human standards to non-human cultures.” To this cool relativism, McCoy replies, “There are certain absolutes, Mr. Spock, and one of them is the right of humanoids to a free and unchained environment, the right to have conditions which permit growth.”

Kirk agrees with McCoy. Spock—who in later episodes invokes the Vulcan slogan celebrating “infinite diversity in infinite combinations”—is comfortable observing Vaal’s servants nonjudgmentally, like specimens behind glass. But Kirk believes there must be deeper, universal principles underlying and limiting diversity, to prevent its degeneration into relativism and nihilism.

Spock’s Relative Hesitation

This is an insight Kirk shares with Abraham Lincoln, who—as we learn in a later episode—is Kirk’s personal hero. When in 1858 Stephen Douglas claimed to be so committed to democracy that he did not care whether American states and territories adopted pro- or anti-slavery constitutions, Lincoln parodied his relativism as meaning “that if one man would enslave another, no third man should object.” Instead, Lincoln insisted, the basis of legitimate democracy was the principle of equality articulated in the Declaration of Independence. Without that frame firmly in place, democracy could claim no moral superiority to tyranny.

Roddenberry’s generation emerged from World War II committed to a liberalism that believed in prosperity, technological progress, and universal humanity.

Spock, by regarding this as a merely “human standard,” and defending Vaal’s suzerainty as “a system which seems to work,” falls into the same relativistic trap as Douglas. By contrast, as Paul Cantor notes, Kirk believes “that all rational beings are created equal,” and extends the Declaration’s proposition “literally throughout the universe.” Kirk orders the Enterprise to destroy Vaal. “You’ll learn to care for yourselves,” he tells the people. “You’ll learn to build for yourselves, think for yourselves, work for yourselves, and what you create is yours. That’s what we call freedom.”

Spock’s hesitation here is an early glimmer of the relativism that would eventually engulf the “Star Trek” universe. Roddenberry’s generation emerged from World War II committed to a liberalism that believed in prosperity, technological progress, and the universal humanity they hoped the United Nations would champion. In the Kennedy years, this technocratic liberalism sought to apply science, the welfare state, and secular culture to raise the standard of living and foster individual happiness worldwide.

Searching for an Impossible Eden

Then came the rise of the New Left—a movement that saw the alleged evils of society as the consequence not merely of capitalism but of technology and reason itself. Civilization was not the perfection of nature or even a protection against nature, but an alienation from nature. Throw off its shackles, and man could reunite with the universe; unfairness would fall away, and peaceful coexistence would reign.

The war in Vietnam and other crises helped foster a debunking culture that saw American principles of justice as a sham, as cynical rationalizations for American greed, racism, and imperialism.

“Peaceful coexistence” was especially crucial. The war in Vietnam and other crises helped foster a debunking culture that saw American principles of justice as a sham, as cynical rationalizations for American greed, racism, and imperialism. The older generation of liberals—and their literary proxies, including Captain Kirk—hardly knew what to make of it, or of the “turn on, tune in, drop out” escapism that often accompanied it.

The original Star Trek savagely parodied such Age of Aquarius romanticism in the episode “The Way to Eden,” in which the Enterprise encounters a group of space-age hippies searching for a legendary planet where all will be equal, without technology or modernity, living off the land. Almost all of Kirk’s crew regard these star-children as deluded, and their longing for prelapsarian harmony does turn out to be a deadly illusion: the Eden planet they find is literally poison—all the trees and even the grass are full of an acid that kills them almost the instant they arrive. Kirk is hardly surprised. All Edens, in his eyes, are illusions, and all illusions are dangerous.

Spock is more indulgent. “There are many who are uncomfortable with what we have created,” he tells the captain, “the planned communities, the programming, the sterilized, artfully balanced atmospheres.” Spock insists he does not share their views, yet he secretly admires them, and devotes his considerable scientific skills to helping locate their paradise planet. Later, he tells one of the few survivors of the acid, “It is my sincere wish that you do not give up your search for Eden. I have no doubt but that you will find it, or make it yourselves.” The skeptical, spirited Kirk could never utter such words.

Tale of Two Hamlets

Kirk, it turns out, has personal reasons for his skepticism. In “The Conscience of the King,” we learn that he is something of a Holocaust survivor himself. When he was young, he and his parents barely escaped death at the hands of the dictator Kodos the Executioner, who slaughtered half the population of the colony on Tarsus IV. Having eluded capture, Kodos lived 20 years under an assumed name, making a living as a Shakespearean actor, until one of Kirk’s fellow survivors tracks him down. Now Kirk must decide whether the actor is really the killer.

For Shakespeare, justice is less about the good prospering and the bad suffering than about a harmony between the world of facts in which we live and the world of words we inhabit.

Aired in 1966, this episode is a commentary on the pursuit of Nazi war criminals, and it typifies the original Star Trek’s moral outlook. During the show’s three seasons, more than 20 former Nazis were tried for their roles in the Holocaust, including five who only two weeks after this episode aired were convicted for working at the Sobibór extermination camp. Intellectuals like Hannah Arendt were preoccupied with the moral and jurisprudential questions of Nazi-hunting. “Conscience” puts these dilemmas into an ambitiously Shakespearean frame.

Like Hamlet, Kirk faces a crisis of certainty. “Logic is not enough,” he says, echoing Hamlet’s “What a rogue and peasant slave am I” soliloquy. “I’ve got to feel my way—make absolutely sure.” Yet one thing Kirk is already sure about is justice. Hamlet may curse that he was ever born to set things right, but he knows it is his duty. Likewise Kirk. When McCoy asks him what good it will do to punish Kodos after a lapse of two decades—“Do you play god, carry his head through the corridors in triumph? That won’t bring back the dead”—Kirk answers, “No. But they may rest easier.”

For Shakespeare, justice is less about the good prospering and the bad suffering than about a harmony between the world of facts in which we live and the world of words we inhabit as beings endowed with speech. When the two fall out of sync—when Claudius’s crime knocks time “out of joint”—the result is only a perverse and temporary illusion. And Kirk is, again, not impressed by illusions. “Who are you to [judge]?” demands Kodos’s daughter. Kirk’s devastating reply: “Who do I have to be?”

Inverting “Star Trek’s” Original Liberalism

This clear-headedness had evaporated by December 1991, when the movie sequel “Star Trek VI: The Undiscovered Country” appeared, only months after Roddenberry’s death. The previous films had focused on questions of loyalty, friendship, and Spock’s need for feeling to leaven his logic, but this one, written in part by Nimoy, would be the first devoted expressly to political subjects. It comments on the waning of the Cold War by portraying the first steps toward peace with the Klingons. Yet the price of peace, it turns out, is not merely to forgive past crimes, but for the innocent peoples of the galaxy to take the guilt upon themselves.

The price of peace, it turns out, is not merely to forgive past crimes, but for the innocent peoples of the galaxy to take the guilt upon themselves.

“Star Trek VI” opens with a shocking betrayal: without informing his captain, Spock has volunteered the crew for a peace mission to the Klingons. Kirk rightly calls this “arrogant presumption,” yet the Vulcan is never expected to apologize.

On the contrary, the film summarily silences Kirk’s objections. At a banquet aboard the Enterprise, he is asked whether he would be willing to surrender his career in exchange for an end to hostilities, and Spock swiftly intervenes. “I believe the captain feels that Starfleet’s mission has always been one of peace,” he says. Kirk tries to disagree, but is again interrupted. Later, he decides that “Spock was right.” His original skepticism toward the peace mission was only prejudice: “I was used to hating Klingons.”

This represented an almost complete inversion of “Star Trek’s” original liberalism, and indeed of any rational scale of moral principles at all. At no point in the show’s history had Kirk or his colleagues treated the Klingons unjustly, whereas audiences for decades have watched the Klingons torment and subjugate the galaxy’s peaceful races.

In “Errand of Mercy,” they attempt genocide to enslave the Organians. In “The Trouble with Tribbles,” they try to poison a planet’s entire food supply. The dungeon in which Kirk is imprisoned in this film is on a par with Stalin’s jails. Yet never does the Klingon leader, Gorkon, or any of his people, acknowledge—let alone apologize for—such injustices. Quite the contrary; his daughter tells a galactic conference, “We are a proud race. We are here because we want to go on being proud.” Within the context of the original “Star Trek,” such pride is morally insane.

Kirk can hardly be blamed for withholding forgiveness, considering that the Klingons have never asked for it.

Yet in service to Spock’s mission of elevating peace over right, the film portrays the Klingons not as thugs, but as misunderstood casualties of human bigotry. Kirk and his crew, says Gorkon’s daughter at the Enterprise banquet, represent a “homo sapiens-only club,” devoted to such chauvinistic values as “inalienable human rights.” “Why, the very name,” she quips, “is racist.” Gorkon’s pacific overtures are stymied by conspirators who assassinate him, and while pursuing the murderers, Kirk decides that he, too, is at fault—because he has not simply let bygones be bygones.

Abashed, he confesses, “I couldn’t get past the death of my son”—a reference to an earlier film in which a Klingon crew stabs his son to death in an effort to extort the secret of a devastating weapon. Kirk can hardly be blamed for withholding forgiveness, considering that the Klingons have never asked for it. Yet “Star Trek VI” demands that Kirk let go of his grievances—and the galaxy’s—unasked, and accept that they will forever go unredressed. Justice is only a human cultural construct.

There Is Nothing to Forgive

The contrast with “Conscience of the King” is jarring. It even affects the many Shakespearean references that pepper both dramas. For the orthodox bard, repentance is always a precondition of forgiveness, and conscience is the inescapable enforcer of natural law.

Kirk learns not only to suffer slings and arrows, but to cease calling it outrageous.

Thus in “Conscience,” Shakespeare’s meditations illuminated Kirk’s thoughts on guilt and judgment. But in the film, the poet is quoted only to obfuscate. “Star Trek VI” even twists Shakespeare’s actual words. The “Undiscovered Country” of the title—to which Gorkon proposes a toast at the banquet—is not, as he claims, “the future,” but Hamlet’s metaphor for death. “‘To be or not to be,’ that is the question which preoccupies our people,” another Klingon tells Kirk.

Yet where Hamlet sought the resolve to take up arms against a sea of troubles, Kirk learns not only to suffer slings and arrows, but to cease calling it outrageous. When he does, Gorkon’s daughter congratulates him for having “restored” her father’s “faith.” But Kirk is a victim of Klingon aggression—he needs no redemption.

Roddenberry was so bothered by the film’s script that he angrily confronted director Nicholas Meyer at a meeting, futilely demanding changes. He and those who helped him create “Star Trek” knew that without a coherent moral code—ideas they considered universal, but which the film calls “racist”—one can never have genuine peace. “Star Trek VI” seemed to nod contentedly at the haunting thought Aleksandr Solzhenitsyn voiced in “The Gulag Archipelago”: “No, no one would have to answer.”

Next-Generation Nihilism

This moral weariness highlighted the moral disarray into which the franchise had fallen. By 1987, when the new Enterprise was being launched on the new series “Star Trek: The Next Generation,” the liberal landscape had changed.

Time and again, the show featured false equivalency on a grand scale.

The show premiered a year after feminist philosopher of science Sandra Harding referred to Newton’s “Principia” as a “rape manual,” and a year before Jesse Jackson led Stanford student protesters chanting, “Hey, hey, ho, ho, Western Civ has got to go!” The Kennedy-esque anti-Communist in the White House was now Ronald Reagan, a former Democrat and union leader who thought the party had left him.

“Next Generation’s” Captain Jean-Luc Picard (Patrick Stewart) was more committed to coexistence and non-intervention than to universal liberty and anti-totalitarianism. Following Spock’s lead, Picard would elevate the Prime Directive into a morally obtuse dogma and would seek ways to evade the responsibility of moral judgment. Time and again, the show featured false equivalency on a grand scale, coupled with the hands-off attitude that the Kirk of “The Apple” had dismissed as complicity with evil.

Consider the episode “Redemption.” Picard has overseen the installation of Gowron as chief of the Klingon Empire, a decision that, although unorthodox, follows Klingon law. The empire, now humanity’s ally, had invited Picard to judge the leadership controversy, and the Enterprise’s Klingon crewman, Mr. Worf (Michael Dorn), has even resigned to join Gowron’s crew. But at just this moment, rivals to the throne revolt and attack Gowron’s ship in full view of the Enterprise.

In “Star Trek VI,” Kirk nearly gave his life trying to prevent the assassination of the Klingon chancellor, but Picard, rather than defend the lawful leader of an ally against a revolt of which he had been forewarned—and which takes place in his presence—chooses to abandon Gowron, and his friend and shipmate Worf. He orders the Enterprise to withdraw, rather than be drawn into a battle his own actions helped precipitate.

When it comes to the universe of real suffering, real need, and a real search for truth, he is content not to decide, not to take responsibility, and not to know.

If that were not enough, Gowron—who manages to survive this fickleness—requests aid against the rebels, whom they all know to have been collaborating with the Romulans, deadly enemies of both the Klingons and humans. Yet Picard again refuses, citing the non-interference directive that Gowron has already waived by requesting assistance. Picard, the Klingons learn, is not a very valuable friend.

What accounts for this incoherent foreign policy? Nothing less than Picard’s commitment to non-commitment. He represents a new, non-judgmental liberalism far shallower than that embraced in Roddenberry’s era. Where Kirk pursues justice, Picard avoids conflict. Just as Kirk’s devotion to universal principles goes deeper than politics, so does Picard’s sentimentalism. When it comes to the universe of real suffering, real need, and a real search for truth, he is content not to decide, not to take responsibility, and not to know.

Full-Blown Insurrection

If “The Apple,” was the perfect expression of the older “Star Trek,” the culminating moment in Next Generation is the 1998 feature film, “Insurrection.” It opens with Picard lamenting that he’s been relegated to boring diplomatic roles. “Can anyone remember when we used to be explorers?” he grumbles.

But soon he learns better. The Enterprise crew is introduced to the Ba’ku people, who live in the kind of agrarian idyll that the space hippies had sought in “The Way to Eden.” Although filmed like a Crate & Barrel ad and scored with pastoral melodies, the Ba’kus’ village is shockingly primitive. They rake, plow, weed, and blacksmith by hand—not because they don’t know better, but because they reject modern devices: “This village is a sanctuary of life,” one of them, Sojef, tells Picard:

Our technological abilities are not apparent because we have chosen not to employ them in our daily lives. We believe when you create a machine to do the work of a man, you take something away from the man.
Anij: But at one time, we explored the galaxy just as you do…
Picard: You have warp capability?
Anij: Capability, yes. But where can warp drive take us, except away from here?

The Ba’ku would have nauseated Captain Kirk. Here is a species that lives “The Apple” not as captives but as willing participants. They have given up growth for stagnation, which they have mistaken for life. Yet the audience is expected to admire this. From this meeting, Picard learns not to long for his days exploring strange new worlds.

In a denouement ultimately cut from the film, Picard encounters Quark (Armin Shimerman), a member of the Ferengi, a race of greedy capitalists. Now that the Ba’ku are safe, Quark fantasizes about developing their home planet. Picard fends him off. “This world is about to become a Federation protectorate,” he says, “which will end any and all attempts at exploitation by people like you.”

They have given up growth for stagnation, which they have mistaken for life.

Let’s ignore the whiff of racism in the phrase “people like you”—when Quark asks “how five thousand time-share units…right there along the lake, would be ‘exploiting’ anyone,” it is a perfectly reasonable question. But Picard snidely laughs it off, and, turning to the Ba’ku, tells them that “The ‘mighty’ Federation could learn a few things from this village.”

What, Kirk would have demanded, could the Federation possibly learn from this village? A village that has chosen not to explore, that has rejected modern agricultural methods, that has given up growth and life in exchange for an absurd fetishizing of manual labor—for the fundamentally childish notion that you “take something” from people when you create tools and techniques that feed the hungry and liberate people to explore the galaxy.

Roddenberry’s generation of “Star Trek” writers would have thought Picard’s words hopelessly reactionary—to be precise, inhuman. But by the end of “Next Generation,” the liberalism that once preached technological progress and human reason has reversed its priorities and now regards “progress” as incipient colonization and a threat to diversity and the environment.

From Principles to Physical Urges

“Star Trek’s” latest iterations—the “reboot” films directed by J.J. Abrams—shrug at the franchise’s former philosophical depth. In 2009, Abrams admitted to an interviewer that he “didn’t get” “Star Trek.” “There was a captain, there was this first officer, they were talking a lot about adventures and not having them as much as I would’ve liked. Maybe I wasn’t smart enough.” His films accordingly eschew the series’ trademark dialogues about moral and political principles, and portray the young Kirk and crew as motivated largely by a maelstrom of lusts, fears, and resentments.

J. J. Abram’s films portray the young Kirk and crew as motivated largely by a maelstrom of lusts, fears, and resentments.

A prime symbol of this transformation is Khan, the villain who appeared first in the 1967 episode “Space Seed,” then in the second “Star Trek” film in 1982 (played both times by Ricardo Montalban), and most recently in Abrams’s 2013 “Star Trek Into Darkness” (in which he was portrayed by Benedict Cumberbatch).

Khan presents a serious challenge to the series’ liberal conception of equality because he is a genetically modified superman. As the late Harry V. Jaffa was fond of observing, Aristotle’s distinction between men, beasts, and gods “remains the framework of the thought of the Declaration of Independence,” according to which “any attempt of human beings to rule other human beings, as if the former were gods, and the latter beasts, is wrong.” But Khan actually is more than a man, which raises a serious problem for mankind’s right to liberty.

In the original TV show’s episode, and somewhat against his grain, it is Spock who addresses the issue. When Kirk calls Khan “the best of the tyrants,” Spock is appalled:

Spock: Gentlemen, this romanticism about a ruthless dictator is—
Kirk: Mister Spock, we humans have a streak of barbarism in us. Appalling, but there, nevertheless.
Scotty: There were no massacres under his rule.
Spock: And as little freedom.

Kirk finally explains, “We can be against him and admire him all at the same time,” which Spock characterizes as “illogical.” In the end, the crew refuses to submit to Khan’s assertion of a eugenic right to rule. Yet they also choose not to punish him even after he tries to kill Kirk and commandeer the Enterprise.

Instead, they leave him and his followers on an unpopulated planet, where he can put his talents to work pioneering a new civilization. Fifteen years later, we learn in the film “Star Trek II” that the planet was devastated by a natural disaster soon afterwards, killing many of Khan’s followers. Obsessed with revenge, Khan manages to escape and, like a space-age Ahab, hunts the aging Kirk. Only by sacrificing his life does Spock save his shipmates.

Government by Accident and Force

By the time Khan reappears under Abrams’s direction, the fixed moral stars by which the franchise once steered have been almost entirely obscured. No longer the thoughtful, bold captain, the young Kirk (Chris Pine) is now all rashness and violence, taking and breaking everything around him. He confesses that he has no idea what he is doing.

Abrams grounds Kirk’s authority not on practical wisdom or merit, but on a version of the swaggering pretension to inherent superiority that ‘Space Seed’ had repudiated.

But these are not vices he outgrows. Instead, the other characters come to recognize these traits as proof of his entitlement to command. When, in Abrams’s first film, Kirk’s recklessness briefly costs him his ship, his reign is restored by the intercession of an older version of Spock, played by Leonard Nimoy, who journeys across the dimensions to counsel Kirk that it is still his “destiny” to lead. “[T]his is the one rule you cannot break,” Nimoy intones, without further explanation.

Kirk proceeds to retake control of the Enterprise in brutal fashion. Abrams thus grounds Kirk’s authority not on practical wisdom or merit, which he expressly disclaims, but on a version of the swaggering pretension to inherent superiority that “Space Seed” had repudiated. The new Enterprise is governed more by what “The Federalist” calls “accident and force” than by “reflection and choice.”

This creates a paradox when the crew encounters Khan in “Into Darkness.” Dispatched to arrest the perpetrator of a terrorist attack, Kirk learns it is Khan—“genetically engineered to be superior so as to lead others to peace in a world at war,” Khan explains—and that earth’s current military leadership were secretly employing him as a military strategist. “I am better,” Khan says, at “everything.”

But this is how Kirk, too, is depicted—as destined to command just because he is “better.” “[I]f Khan and Kirk have the same motivation,” asked critic Abigail Nussbaum, “why is one of them the bad guy and the other the hero?”

Ultimately, Khan is presented as evil not because he wars against equality and freedom, but because he isn’t one of us, while Kirk is—and because he loses, while Kirk wins.

The film acknowledges the similarities between the two, and even enlists the audience’s sympathy for Khan’s terrorism—but it never answers this question, except in terms of personal loyalty and betrayal. In an effort at ratio ex machina, Nimoy is once again brought in as Spock, to tell the crew that Khan is “dangerous”—but even he gives the audience no reason to consider Khan a villain.

Ultimately, Khan is presented as evil not because he wars against equality and freedom, but because he isn’t one of us, while Kirk is—and because he loses, while Kirk wins. This arbitrariness infects the film’s single effort to express an abstract principle: “Our first instinct is to seek revenge when those we love are taken,” says Kirk in the final scene. “But that’s not who we are.” We are not told why not, beyond this tribalistic assertion. But it is who Khan is, and he is better at everything. Doesn’t that make vengeance right?

Having lost their principles, the show’s heroes cannot really explain, or understand, what differentiates them from their enemies, and so are rendered vulnerable to the very forces they once opposed. That Nimoy was recruited to bless this arrangement on behalf of “Star Trek’s” older generation is perverse.

But that perversity is the natural consequence of the breakdown in the liberal principles that once guided the series. “Star Trek’s” romance with relativism gradually blotted them out until the franchise came to prize feeling over thought, image over substance, and immediate gratification over moral and political responsibility. What was once an expression of the Enlightenment faded “into darkness.”

Over nearly 50 years, “Star Trek” tracked the devolution of liberalism from the philosophy of the New Frontier into a preference for non-judgmental diversity and reactionary hostility to innovation, and finally into an almost nihilistic collection of divergent urges. At its best, “Star Trek” talked about big ideas, in a big way. Its decline reflects a culture-wide change in how Americans have thought about the biggest idea of all: mankind’s place in the universe.

Timothy Sandefur is a principal attorney at the Pacific Legal Foundation, and the author of “The Conscience of the Constitution: The Declaration of Independence and the Right to Liberty” (Cato Institute).